Anyone with a fear of spiders will tell you that they are not the most pleasant creatures. Hairy legs, multiple eyes, piercing fangs; their appearance is often terrifying, even if they aren’t that big! But what’s more, some are even more awful than they appear. In addition to the lethal venom that they produce, their aggressive style of attack is enough to make anyone run a mile! Here’s the 5 you need to know about and steer well clear of.5. The Six eyed sand spider (Sicarius hahni)Measuring up to 2 inches in length, including legs, these arachnids live in the deserts of southern Africa. Unlike any other, these spiders bury themselves in the sand so they can ambush their prey. Described as having a haemolytic and necrotic effect on the body, their venom is particularly powerful. The venom causes a rupture of blood vessels and destruction of cell tissue. What’s more, there is no antidote to this so unfortunately once you’ve been bitten, there’s not a lot you can do. Fortunately, the spider is quite shy in nature so bites are rare. 4. The Black Widow (Latrodectus mactans)Originating from North America, the Black Widow is recognisable by its distinctive black colour and the red hourglass shape on its back. They’re quite small and are generally no longer than half an inch in females, the males being even smaller. Even though they may not appear as aggressive as other spiders, the Black Widow’s venom is very powerful and contains a substance called latrotoxin. This toxin causes an excessive release of neurotransmitters which will, in turn, trigger illnesses such as headaches, muscle spasms, nausea etc. Even though it can have a profound effect on the human body, bites are very rarely fatal. A course of medication is usually enough to cure the effects within a few days. While other black widow species may also be listed as the most dangerous spiders, they deliver a lower amount of venom than Latrodectus mactans.3. The Australian funnel-web spider (Atrax robustus)Native to Australia, this species is undoubtedly the most famous of the tarantulas. More specifically, they can be found in Sydney and its surrounding areas. They have a glossy black colour and are generally around 2 inches long. However, they have been known to grow to almost 3 inches. The Atrax robustus are known to be very aggressive. When they feel threatened or bothered, they stand on their hind legs and show their massive fangs.Sometimes, when they bite repeatedly, the spiders deliver powerful venom that is highly toxic to primates including humans. There is an antidote to its venom but it must be administered within the first hour of being bitten. Otherwise, it can be fatal, especially in children and more vulnerable individuals. 2. The Chilean recluse spider (Loxosceles laeta)This spider is part of the Loxosceles genus, sometimes called recluses or spider violinists. This name refers to their brown appearance and the marks on their body, making it look like the musical instrument. Loxosceles laeta is native to South America but is now present in several other countries including the United States. Measuring up to an inch and half including legs, they are considered as one of the worst of the recluse spiders because of the power of its venom. Like others, Loxosceles laeta creates a toxin that attacks cell tissue. However, the reaction varies from one individual to another, particularly depending on the amount of venom released into the body. The effects on the body can range from simple skin irritation to deep tissue necrosis. In this case, the skin hollows out revealing dead and black skin tissue. This type of injury is very painful and takes several weeks to heal. This is particularly evident if treatment is not administered within 48 hours of the bite.More common effects of the bite are illnesses such as nausea, but often, a Loxosceles bite is not fatal. Furthermore, these spiders are shy and only bite when they are in accidental contact with the skin. In the United States, there is another spider like this one, known as the brown recluse (Loxosceles reclusa).1. The Brazilian wandering spider (Phoneutria Fera)If you come across this spider, you’d be wise to move past it and carry on your way as fast as possible. Belonging to the Phoneutria family, they are also known as banana spiders, for their tendency to hide in the fruit, buried within the bunches. They can be found in South America, particularly in Brazil and Peru, where they can grow up to 6 and a half inches wide.Like others, they are known to be very aggressive and to bite several times if they are disturbed. They then inject their venom, considered the most active among all species of spiders. So powerful, it’s recognised by the Guinness World Records as one of the most toxic to humans. According to tests, their venom is so powerful that 0.006 milligrams are enough to kill a mouse.The substance can have toxic effects on the brain potentially leading to high blood pressure, nausea, vertigo, convulsions and even hyperthermia. It also causes a tremendous amount of physical pain. If bitten, you need to seek immediate treatment as it can take days or even weeks to heal. Every year, Phoneutria are responsible for hundreds of bites but they are rarely fatal thanks to an effective antidote. Check out the video above for more on these 5 terrifying arachnids!